1. Field of the Invention
The present invention relates to an image-capturing apparatus, in particular to the storage of an image file in a storage medium of the image-capturing apparatus.
2. Description of the Related Art
An image-capturing apparatus, for example a digital camera, processes image data, and stores it in a memory device. Some digital cameras have memory devices, for example, a built-in flash memory and a detachable external memory medium. A detachable external memory medium can be a memory card, for example an SD CARD™, or optical disc, for example a CD-R.
In general, the amount of time required to store image data in a memory device is longer than the amount of time required for imaging and processing. An overly long storage time can cause the processed image data not to be stored. It increases the interval time until the next time that the camera is ready to photograph a photographic subject. In other words, the maximum number of photographs able to be taken per second depends on the writing speed of the memory device.
Some digital cameras are required to photograph a subject, continuously. Continuous photographing demands fast writing speed of the memory device. Fast writing speed increases the maximum number of photographs able to be taken per second.
The writing speed of a memory device is different for different types or generations of memory. Each memory device provided in a digital camera has an attribute, for example the writing speed. A digital camera which increases the number of photographs able to be taken per second by storing the image data in a memory device having an attribute of the fastest writing speed among memory devices is disclosed in Japanese Unexamined Patent Publication (KOKAI) No. (HEI) 5-49000.
However, this attribute indicates the average writing speed of a memory device. The memory area of a memory device fragments into many small areas through the repetition of storing image data. This fragmentation interferes with storage of the image data in a continuous memory area, increases writing time, reduces writing speed, and increases the difference between the actual writing speed and the average writing speed. A digital camera storing image data into a memory device having a slow writing speed due to the average writing speed being different from the actual writing speed, cannot perform to show its potential.